From mboxrd@z Thu Jan 1 00:00:00 1970 From: Darwin Rambo Date: Fri, 31 Jan 2014 10:18:57 -0800 Subject: [U-Boot] [PATCH 6/6] board: bcm28155_ap: Add board files In-Reply-To: <52EBDA14.4060303@ti.com> References: <1390848810-7227-1-git-send-email-drambo@broadcom.com> <1390848810-7227-7-git-send-email-drambo@broadcom.com> <20140129223344.GY3277@bill-the-cat> <52EADACA.4040703@broadcom.com> <52EBB060.5020207@ti.com> <52EBDA14.4060303@ti.com> Message-ID: <52EBE911.6030505@broadcom.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 14-01-31 09:15 AM, Tom Rini wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > On 01/31/2014 12:05 PM, Tim Kryger wrote: >> On Fri, Jan 31, 2014 at 6:17 AM, Tom Rini wrote: >>> On 01/30/2014 06:05 PM, Darwin Rambo wrote: >>>> We tried using this on our reference board and it hangs accessing >>>> memory regions that are not populated. Our memory controller >>>> doesn't appear to properly support accessing regions that are not >>>> backed by physical sdram. So I think it's best to keep this code as >>>> is and consider this approach for future designs. >>> >>> Wait, what did you do? get_ram_size(base, max) must work and return >>> CONFIG_SYS_SDRAM_SIZE, or you haven't properly configured your >>> controller (as get_ram_size just pokes parts of the specified range). >> >> Tom, >> >> In my experience, there are three general ways memory controllers >> behave when an access is made to an address that could be backed by >> RAM but isn't on a particular board. >> >> 1. All reads return a fixed pattern and writes are ignored >> 2. A bus error is triggered that the CPU sees as a data abort >> 3. No response to the transaction so the bus and CPU lock up >> >> I believe the Broadcom memory controller can only behave in the third, >> least desirable way. > > That's fine. You should still use get_ram_size(base, > CONFIG_SYS_SDRAM_SIZE) like other platforms use as this go above the max > size it's given. If this hangs, you have a problem with your > configuration of the memory controller. Make sense? Yes. We have tested that this works and will implement this way. Thanks. > > - -- > Tom > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.11 (GNU/Linux) > Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ > > iQIcBAEBAgAGBQJS69oUAAoJENk4IS6UOR1Wf/AP/2ApLwjAffxJ7LmEFFEK7hlr > +dq1FW9ZRppfLRbfUrZz8Q/muyrx1ZuF9pIjjrFxLkNSLS3t8LZrJmfeswePqGC+ > dq6qLl+ovk0VNYsxEhS77j1QQ/LLri67QCiGEZuS8vDB7qxiyuuCXkzyyW8hRFZ7 > yfKpbfdRYpzWTJhAYnB0b1OaBi1jamsnjhXNU5XNa/H3PfDDofNA2fFQQfKbleOH > BVOka1LP/+28gqKksEziM9cbcjPYJdE/FfY75nkbqKl9PWl+qIUZli90QO3Qdbgy > uJJB1d3v6amfHZYbJymR3r8FoRjjCKxnCza5rCLpwFLxAKCUIIGHBFUGpvdcFoVa > YctuEu2Dx2SgQ9dEGbLT1d2bsbfxOATEr5CyCpD7vD/9e/Ze7XaXALVKocfQmDbs > 77s0YvHuXLGQPudPzYrEqPvgxf/NlNjeLj5IWqF++AE3j5U1sE26x95qk8jobMSn > KjYGwzsxnd/gErqiYBawkrHxS2f4beAucsoprCh0WmSXiqSh6Wzc/+XlAIVSV7vm > UE969gAzP1F2j37QfWR2/B0ILP27Pk3Ano8Dj2MIVKCAVkkpSQ5SCqAA7wvMzHej > 801O52kArhG3/G/WrAbeLoQxKsdUyNI92+T0UaquTI4hRZk5GSvHQNCaZAcx6fCa > hZ1o6zG9nMsp/yzVe7VZ > =0yIj > -----END PGP SIGNATURE----- >